A wavelet-based technique was used for the identification of bubble events from the velocity-time data obtained using LIDA in bubble column reactors. Bubble rise velocity distribution was also measured from the velocity-time series, which enabled the estimation of bubble size and shape distributions. From this information, the values of local fractional gas hold-up (epsilon (G)) and effective interfacial area ((a) under bar) were calculated. The estimated values of (a) under bar have been compared with those obtained from the chemical method of air-oxidation of sodium sulfite. For this purpose, LIDA measurements were carried out during the reaction of sulfite oxidation.